Question

The pH of an acid solution is 5.82. Calculate the Ka for the monoprotic acid. The initial acid concentration is 0.010 M.

Answer 1

The answer is

`Ka = 2.29 * {10}^( - 14) moldm^( - 3)`

Step-by-step explanation:

The Ka of an acid when given the pH and concentration can be found by

`pH = - (1)/(2) log(Ka) - (1)/(2) log(c)`

where

c is the concentration of the acid

From the question

pH = 5.82

c = 0.010 M

Substitute the values into the above formula and solve for Ka

We have

`5.82 = - (1)/(2) log(Ka) - (1)/(2) log(0.010)`

`- (1)/(2) log(Ka) = 5.82 + 1`

`- (1)/(2) log(Ka) = 6.82`

Multiply through by - 2

`log(Ka) = - 13.64`

Find antilog of both sides

We have the final answer as

`Ka = 2.29 * {10}^( - 14) moldm^( - 3)`

Hope this helps you